1. Technical Field
The present invention relates to a composite-material structure having a hole and to an aircraft main wing and an aircraft fuselage provided with the same.
2. Description of the Related Art
In the fields of, for example, aircraft, ships, vehicles, etc., composite materials made of fiber reinforced plastics (FRP: Fiber reinforced Plastics) are widely employed as high-strength, lightweight structures. A hole sometimes is formed in such composite materials to provide access for inspection and during assembly. In the case where the hole is formed, because stress concentration occurs at the circumferential edge of the hole, the strength at the circumferential edge of the hole needs to be enhanced.
Patent Literature 1 described below discloses an invention that, to reinforce the circumferential edge of an access hole in the skin of an aircraft, increases the thickness thereof by adding a reinforcing layer, thus increasing the strength thereof. The reinforcing layer disclosed in Patent Literature 1 is secured to a base with pins or stitches to prevent it from peeling off when subjected to a load.